Stenosis within arteries and other blood vessels may be treated by permanently or temporarily introducing a stent into the stenosed region to open the lumen of the vessel. The stent may be introduced into the desired blood vessel using known percutaneous or transluminal methods. A catheter, having the stent securely crimped thereon, may be directed to the region of the blood vessel being treated. The catheter may be positioned such that the stent is centered across the stenosed region. Balloon inflation may then be used to expand the stent radially, thereby engaging the stenosed material. As the stent expands, the material is forced outward, dilating the lumen of the blood vessel. Due to the substantial radial force of the stent construction, the stent retains its expanded shape, providing an open passage for blood flow. The balloon is then deflated and the catheter withdrawn.
A stent may be typically constructed from a mesh or coiled material. Stenotic material trapped between the stent and the vessel wall may extend into the openings in the mesh or coil, and may be sheared off by the longitudinal compression of the stent to create loose embolic debris. When this material travels downstream, it can cause serious complications. For example, loose embolic material released within the ascending aorta, the aortic arch, or the carotid arteries may travel downstream to the brain, possibly causing stroke, which can lead to permanent injuries or even death of the patient.
In-line filters, such as mesh or mesh wire filters, have been used to attempt to filter embolic material downstream of the stent. A drawback of such filters is that they generally are not compatible with previously known delivery devices. Another drawback is that with time the filter fills and degrades in performance or occludes the lumen.